#include<iostream>
#include <string>
using namespace std;

int main()
{
	string s1;
	string s2("hello world.");
	string s3 = "hello world.";
	string s4(s2);
	string s5 = s3;

	//cin >> s1;
	cout << s1 << endl;
	cout << s2 << endl;
	cout << s3 << endl;
	cout << s4 << endl;
	cout << s5 << endl;


	string s7(s2, 6, 5);
	string s8(s2, 6, 15);
	string s9(s2, 6);
	string s10(s2, 6, string::npos);

	cout << s7 << endl;
	cout << s8 << endl;
	cout << s9 << endl;
	cout << s10 << endl;

	string s11(s2, 3);
	//string s12(s2, 23);

	cout << s11 << endl;

	string s13(23, 'c');
	cout << s13 << endl;


	char c1 = s2[0];
	cout << c1 << endl;
	s2[7]='3';
	cout << s2 << endl;


	return 0;
}